fs/btrfs/acl.c - linux - Git at Google

 /*
  * Copyright (C) 2007 Red Hat.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public
  * License v2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * General Public License for more details.
  *
  * You should have received a copy of the GNU General Public
  * License along with this program; if not, write to the
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 021110-1307, USA.
  */

 #include <linux/fs.h>
 #include <linux/string.h>
 #include <linux/xattr.h>
 #include <linux/posix_acl_xattr.h>
 #include <linux/posix_acl.h>
 #include <linux/sched.h>
 #include <linux/slab.h>

 #include "ctree.h"
 #include "btrfs_inode.h"
 #include "xattr.h"

 #ifdef CONFIG_BTRFS_FS_POSIX_ACL

 static struct posix_acl *btrfs_get_acl(struct inode *inode, int type)
 {
 	int size;
 	const char *name;
 	char *value = NULL;
 	struct posix_acl *acl;

 	if (!IS_POSIXACL(inode))
 		return NULL;

 	acl = get_cached_acl(inode, type);
 	if (acl != ACL_NOT_CACHED)
 		return acl;

 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		name = POSIX_ACL_XATTR_ACCESS;
 		break;
 	case ACL_TYPE_DEFAULT:
 		name = POSIX_ACL_XATTR_DEFAULT;
 		break;
 	default:
 		BUG();
 	}

 	size = __btrfs_getxattr(inode, name, "", 0);
 	if (size > 0) {
 		value = kzalloc(size, GFP_NOFS);
 		if (!value)
 			return ERR_PTR(-ENOMEM);
 		size = __btrfs_getxattr(inode, name, value, size);
 		if (size > 0) {
 			acl = posix_acl_from_xattr(value, size);
 			if (IS_ERR(acl)) {
 				kfree(value);
 				return acl;
 			}
 			set_cached_acl(inode, type, acl);
 		}
 		kfree(value);
 	} else if (size == -ENOENT || size == -ENODATA || size == 0) {
 		/* FIXME, who returns -ENOENT?  I think nobody */
 		acl = NULL;
 		set_cached_acl(inode, type, acl);
 	} else {
 		acl = ERR_PTR(-EIO);
 	}

 	return acl;
 }

 static int btrfs_xattr_acl_get(struct dentry *dentry, const char *name,
 		void *value, size_t size, int type)
 {
 	struct posix_acl *acl;
 	int ret = 0;

 	if (!IS_POSIXACL(dentry->d_inode))
 		return -EOPNOTSUPP;

 	acl = btrfs_get_acl(dentry->d_inode, type);

 	if (IS_ERR(acl))
 		return PTR_ERR(acl);
 	if (acl == NULL)
 		return -ENODATA;
 	ret = posix_acl_to_xattr(acl, value, size);
 	posix_acl_release(acl);

 	return ret;
 }

 /*
  * Needs to be called with fs_mutex held
  */
 static int btrfs_set_acl(struct btrfs_trans_handle *trans,
 			 struct inode *inode, struct posix_acl *acl, int type)
 {
 	int ret, size = 0;
 	const char *name;
 	char *value = NULL;
 	mode_t mode;

 	if (acl) {
 		ret = posix_acl_valid(acl);
 		if (ret < 0)
 			return ret;
 		ret = 0;
 	}

 	switch (type) {
 	case ACL_TYPE_ACCESS:
 		mode = inode->i_mode;
 		name = POSIX_ACL_XATTR_ACCESS;
 		if (acl) {
 			ret = posix_acl_equiv_mode(acl, &mode);
 			if (ret < 0)
 				return ret;
 			inode->i_mode = mode;
 		}
 		ret = 0;
 		break;
 	case ACL_TYPE_DEFAULT:
 		if (!S_ISDIR(inode->i_mode))
 			return acl ? -EINVAL : 0;
 		name = POSIX_ACL_XATTR_DEFAULT;
 		break;
 	default:
 		return -EINVAL;
 	}

 	if (acl) {
 		size = posix_acl_xattr_size(acl->a_count);
 		value = kmalloc(size, GFP_NOFS);
 		if (!value) {
 			ret = -ENOMEM;
 			goto out;
 		}

 		ret = posix_acl_to_xattr(acl, value, size);
 		if (ret < 0)
 			goto out;
 	}

 	ret = __btrfs_setxattr(trans, inode, name, value, size, 0);
 out:
 	kfree(value);

 	if (!ret)
 		set_cached_acl(inode, type, acl);

 	return ret;
 }

 static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
 		const void *value, size_t size, int flags, int type)
 {
 	int ret;
 	struct posix_acl *acl = NULL;

 	if (!inode_owner_or_capable(dentry->d_inode))
 		return -EPERM;

 	if (!IS_POSIXACL(dentry->d_inode))
 		return -EOPNOTSUPP;

 	if (value) {
 		acl = posix_acl_from_xattr(value, size);
 		if (acl) {
 			ret = posix_acl_valid(acl);
 			if (ret)
 				goto out;
 		} else if (IS_ERR(acl)) {
 			return PTR_ERR(acl);
 		}
 	}

 	ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type);
 out:
 	posix_acl_release(acl);

 	return ret;
 }

 int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags)
 {
 	int error = -EAGAIN;

 	if (flags & IPERM_FLAG_RCU) {
 		if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
 			error = -ECHILD;

 	} else {
 		struct posix_acl *acl;
 		acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
 		if (IS_ERR(acl))
 			return PTR_ERR(acl);
 		if (acl) {
 			error = posix_acl_permission(inode, acl, mask);
 			posix_acl_release(acl);
 		}
 	}

 	return error;
 }

 /*
  * btrfs_init_acl is already generally called under fs_mutex, so the locking
  * stuff has been fixed to work with that.  If the locking stuff changes, we
  * need to re-evaluate the acl locking stuff.
  */
 int btrfs_init_acl(struct btrfs_trans_handle *trans,
 		   struct inode *inode, struct inode *dir)
 {
 	struct posix_acl *acl = NULL;
 	int ret = 0;

 	/* this happens with subvols */
 	if (!dir)
 		return 0;

 	if (!S_ISLNK(inode->i_mode)) {
 		if (IS_POSIXACL(dir)) {
 			acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
 			if (IS_ERR(acl))
 				return PTR_ERR(acl);
 		}

 		if (!acl)
 			inode->i_mode &= ~current_umask();
 	}

 	if (IS_POSIXACL(dir) && acl) {
 		struct posix_acl *clone;
 		mode_t mode;

 		if (S_ISDIR(inode->i_mode)) {
 			ret = btrfs_set_acl(trans, inode, acl,
 					    ACL_TYPE_DEFAULT);
 			if (ret)
 				goto failed;
 		}
 		clone = posix_acl_clone(acl, GFP_NOFS);
 		ret = -ENOMEM;
 		if (!clone)
 			goto failed;

 		mode = inode->i_mode;
 		ret = posix_acl_create_masq(clone, &mode);
 		if (ret >= 0) {
 			inode->i_mode = mode;
 			if (ret > 0) {
 				/* we need an acl */
 				ret = btrfs_set_acl(trans, inode, clone,
 						    ACL_TYPE_ACCESS);
 			}
 		}
 		posix_acl_release(clone);
 	}
 failed:
 	posix_acl_release(acl);

 	return ret;
 }

 int btrfs_acl_chmod(struct inode *inode)
 {
 	struct posix_acl *acl, *clone;
 	int ret = 0;

 	if (S_ISLNK(inode->i_mode))
 		return -EOPNOTSUPP;

 	if (!IS_POSIXACL(inode))
 		return 0;

 	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
 	if (IS_ERR_OR_NULL(acl))
 		return PTR_ERR(acl);

 	clone = posix_acl_clone(acl, GFP_KERNEL);
 	posix_acl_release(acl);
 	if (!clone)
 		return -ENOMEM;

 	ret = posix_acl_chmod_masq(clone, inode->i_mode);
 	if (!ret)
 		ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS);

 	posix_acl_release(clone);

 	return ret;
 }

 const struct xattr_handler btrfs_xattr_acl_default_handler = {
 	.prefix = POSIX_ACL_XATTR_DEFAULT,
 	.flags	= ACL_TYPE_DEFAULT,
 	.get	= btrfs_xattr_acl_get,
 	.set	= btrfs_xattr_acl_set,
 };

 const struct xattr_handler btrfs_xattr_acl_access_handler = {
 	.prefix = POSIX_ACL_XATTR_ACCESS,
 	.flags	= ACL_TYPE_ACCESS,
 	.get	= btrfs_xattr_acl_get,
 	.set	= btrfs_xattr_acl_set,
 };

 #else /* CONFIG_BTRFS_FS_POSIX_ACL */

 int btrfs_acl_chmod(struct inode *inode)
 {
 	return 0;
 }

 int btrfs_init_acl(struct btrfs_trans_handle *trans,
 		   struct inode *inode, struct inode *dir)
 {
 	return 0;
 }

 #endif /* CONFIG_BTRFS_FS_POSIX_ACL */
	/*
	* Copyright (C) 2007 Red Hat. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of the GNU General Public
	* License v2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*
	* You should have received a copy of the GNU General Public
	* License along with this program; if not, write to the
	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	* Boston, MA 021110-1307, USA.
	*/

	#include <linux/fs.h>
	#include <linux/string.h>
	#include <linux/xattr.h>
	#include <linux/posix_acl_xattr.h>
	#include <linux/posix_acl.h>
	#include <linux/sched.h>
	#include <linux/slab.h>

	#include "ctree.h"
	#include "btrfs_inode.h"
	#include "xattr.h"

	#ifdef CONFIG_BTRFS_FS_POSIX_ACL

	static struct posix_acl btrfs_get_acl(struct inode inode, int type)
	{
	int size;
	const char *name;
	char *value = NULL;
	struct posix_acl *acl;

	if (!IS_POSIXACL(inode))
	return NULL;

	acl = get_cached_acl(inode, type);
	if (acl != ACL_NOT_CACHED)
	return acl;

	switch (type) {
	case ACL_TYPE_ACCESS:
	name = POSIX_ACL_XATTR_ACCESS;
	break;
	case ACL_TYPE_DEFAULT:
	name = POSIX_ACL_XATTR_DEFAULT;
	break;
	default:
	BUG();
	}

	size = __btrfs_getxattr(inode, name, "", 0);
	if (size > 0) {
	value = kzalloc(size, GFP_NOFS);
	if (!value)
	return ERR_PTR(-ENOMEM);
	size = __btrfs_getxattr(inode, name, value, size);
	if (size > 0) {
	acl = posix_acl_from_xattr(value, size);
	if (IS_ERR(acl)) {
	kfree(value);
	return acl;
	}
	set_cached_acl(inode, type, acl);
	}
	kfree(value);
	} else if (size == -ENOENT \|\| size == -ENODATA \|\| size == 0) {
	/* FIXME, who returns -ENOENT? I think nobody */
	acl = NULL;
	set_cached_acl(inode, type, acl);
	} else {
	acl = ERR_PTR(-EIO);
	}

	return acl;
	}

	static int btrfs_xattr_acl_get(struct dentry dentry, const char name,
	void *value, size_t size, int type)
	{
	struct posix_acl *acl;
	int ret = 0;

	if (!IS_POSIXACL(dentry->d_inode))
	return -EOPNOTSUPP;

	acl = btrfs_get_acl(dentry->d_inode, type);

	if (IS_ERR(acl))
	return PTR_ERR(acl);
	if (acl == NULL)
	return -ENODATA;
	ret = posix_acl_to_xattr(acl, value, size);
	posix_acl_release(acl);

	return ret;
	}

	/*
	* Needs to be called with fs_mutex held
	*/
	static int btrfs_set_acl(struct btrfs_trans_handle *trans,
	struct inode inode, struct posix_acl acl, int type)
	{
	int ret, size = 0;
	const char *name;
	char *value = NULL;
	mode_t mode;

	if (acl) {
	ret = posix_acl_valid(acl);
	if (ret < 0)
	return ret;
	ret = 0;
	}

	switch (type) {
	case ACL_TYPE_ACCESS:
	mode = inode->i_mode;
	name = POSIX_ACL_XATTR_ACCESS;
	if (acl) {
	ret = posix_acl_equiv_mode(acl, &mode);
	if (ret < 0)
	return ret;
	inode->i_mode = mode;
	}
	ret = 0;
	break;
	case ACL_TYPE_DEFAULT:
	if (!S_ISDIR(inode->i_mode))
	return acl ? -EINVAL : 0;
	name = POSIX_ACL_XATTR_DEFAULT;
	break;
	default:
	return -EINVAL;
	}

	if (acl) {
	size = posix_acl_xattr_size(acl->a_count);
	value = kmalloc(size, GFP_NOFS);
	if (!value) {
	ret = -ENOMEM;
	goto out;
	}

	ret = posix_acl_to_xattr(acl, value, size);
	if (ret < 0)
	goto out;
	}

	ret = __btrfs_setxattr(trans, inode, name, value, size, 0);
	out:
	kfree(value);

	if (!ret)
	set_cached_acl(inode, type, acl);

	return ret;
	}

	static int btrfs_xattr_acl_set(struct dentry dentry, const char name,
	const void *value, size_t size, int flags, int type)
	{
	int ret;
	struct posix_acl *acl = NULL;

	if (!inode_owner_or_capable(dentry->d_inode))
	return -EPERM;

	if (!IS_POSIXACL(dentry->d_inode))
	return -EOPNOTSUPP;

	if (value) {
	acl = posix_acl_from_xattr(value, size);
	if (acl) {
	ret = posix_acl_valid(acl);
	if (ret)
	goto out;
	} else if (IS_ERR(acl)) {
	return PTR_ERR(acl);
	}
	}

	ret = btrfs_set_acl(NULL, dentry->d_inode, acl, type);
	out:
	posix_acl_release(acl);

	return ret;
	}

	int btrfs_check_acl(struct inode *inode, int mask, unsigned int flags)
	{
	int error = -EAGAIN;

	if (flags & IPERM_FLAG_RCU) {
	if (!negative_cached_acl(inode, ACL_TYPE_ACCESS))
	error = -ECHILD;

	} else {
	struct posix_acl *acl;
	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
	if (IS_ERR(acl))
	return PTR_ERR(acl);
	if (acl) {
	error = posix_acl_permission(inode, acl, mask);
	posix_acl_release(acl);
	}
	}

	return error;
	}

	/*
	* btrfs_init_acl is already generally called under fs_mutex, so the locking
	* stuff has been fixed to work with that. If the locking stuff changes, we
	* need to re-evaluate the acl locking stuff.
	*/
	int btrfs_init_acl(struct btrfs_trans_handle *trans,
	struct inode inode, struct inode dir)
	{
	struct posix_acl *acl = NULL;
	int ret = 0;

	/* this happens with subvols */
	if (!dir)
	return 0;

	if (!S_ISLNK(inode->i_mode)) {
	if (IS_POSIXACL(dir)) {
	acl = btrfs_get_acl(dir, ACL_TYPE_DEFAULT);
	if (IS_ERR(acl))
	return PTR_ERR(acl);
	}

	if (!acl)
	inode->i_mode &= ~current_umask();
	}

	if (IS_POSIXACL(dir) && acl) {
	struct posix_acl *clone;
	mode_t mode;

	if (S_ISDIR(inode->i_mode)) {
	ret = btrfs_set_acl(trans, inode, acl,
	ACL_TYPE_DEFAULT);
	if (ret)
	goto failed;
	}
	clone = posix_acl_clone(acl, GFP_NOFS);
	ret = -ENOMEM;
	if (!clone)
	goto failed;

	mode = inode->i_mode;
	ret = posix_acl_create_masq(clone, &mode);
	if (ret >= 0) {
	inode->i_mode = mode;
	if (ret > 0) {
	/* we need an acl */
	ret = btrfs_set_acl(trans, inode, clone,
	ACL_TYPE_ACCESS);
	}
	}
	posix_acl_release(clone);
	}
	failed:
	posix_acl_release(acl);

	return ret;
	}

	int btrfs_acl_chmod(struct inode *inode)
	{
	struct posix_acl acl, clone;
	int ret = 0;

	if (S_ISLNK(inode->i_mode))
	return -EOPNOTSUPP;

	if (!IS_POSIXACL(inode))
	return 0;

	acl = btrfs_get_acl(inode, ACL_TYPE_ACCESS);
	if (IS_ERR_OR_NULL(acl))
	return PTR_ERR(acl);

	clone = posix_acl_clone(acl, GFP_KERNEL);
	posix_acl_release(acl);
	if (!clone)
	return -ENOMEM;

	ret = posix_acl_chmod_masq(clone, inode->i_mode);
	if (!ret)
	ret = btrfs_set_acl(NULL, inode, clone, ACL_TYPE_ACCESS);

	posix_acl_release(clone);

	return ret;
	}

	const struct xattr_handler btrfs_xattr_acl_default_handler = {
	.prefix = POSIX_ACL_XATTR_DEFAULT,
	.flags = ACL_TYPE_DEFAULT,
	.get = btrfs_xattr_acl_get,
	.set = btrfs_xattr_acl_set,
	};

	const struct xattr_handler btrfs_xattr_acl_access_handler = {
	.prefix = POSIX_ACL_XATTR_ACCESS,
	.flags = ACL_TYPE_ACCESS,
	.get = btrfs_xattr_acl_get,
	.set = btrfs_xattr_acl_set,
	};

	#else /* CONFIG_BTRFS_FS_POSIX_ACL */

	int btrfs_acl_chmod(struct inode *inode)
	{
	return 0;
	}

	int btrfs_init_acl(struct btrfs_trans_handle *trans,
	struct inode inode, struct inode dir)
	{
	return 0;
	}

	#endif /* CONFIG_BTRFS_FS_POSIX_ACL */